LAUSR

Abstract A three-dimensional optimum pin fin heat sink (PFHS) design problem is investigated numerically using the Levenberg-Marquardt Method (LMM) and a commercial package, CFD-ACE+, and experimentally under natural convection conditions and the fixed pin fin material constraint. The purpose is to design the optimal pin heights, pin diameters and orientation angles of the PFHS and thus minimize the thermal resistance Rth and enhance the heat dissipation performance of the system. The radiation effect between the PFHS and air is considered in this work. It indicates that when considering only the perimeter pin fins and neglecting the interior pin fins, the optimal heat dissipation performance is obtained. The novelty of this work lies in that a functional form of a tapered pin is established and its optimal design variables are then estimated, which has not been examined previously. Finally, experimental verifications were conducted on the fabricated heat sinks; the temperatures measured by the thermal camera are in good agreement with the numerical temperatures on those heat sinks, since the maximum relative error is less than 3.68% and the maximum discrepancy between computed and measured Rth is smaller than 1.79%. Result reveals that the tapered pin heat sink (design D) with a 66° orientation angle has the lowest thermal resistance among all designs, and its thermal resistance is 18.7% smaller than that of a traditional PFHS, showing the validity of this design algorithm in estimating the optimal variables of the natural convection PFHSs.